本文選題：草魚鱗片 + 仿生減阻　； 參考：《沈陽農(nóng)業(yè)大學(xué)》2017年碩士論文

【摘要】：船板是水稻插秧機(jī)的重要觸泥部件之一,在水田泥水環(huán)境作業(yè)過程中,其與泥水相接觸形成較大的滑行阻力,使得能源浪費(fèi)嚴(yán)重,同時(shí)也降低了作業(yè)效率�？梢�,對于減小插秧機(jī)船板流體阻力的研究,具有重要的意義。本文在國家自然科學(xué)基金項(xiàng)目:插秧機(jī)船板底面鱗片形仿生微結(jié)構(gòu)的減阻機(jī)理研究(51305282)的資助下,以草魚鱗片表面微觀結(jié)構(gòu)作為生物原型,設(shè)計(jì)了具有鱗片型微結(jié)構(gòu)的仿生表面,并分析其減阻特性。將這種微結(jié)構(gòu)仿生應(yīng)用到水稻插秧機(jī)的船板上,進(jìn)一步研究了船板底面泥漿的流動(dòng)摩擦學(xué)特性及其減阻性能。主要研究內(nèi)容與結(jié)論如下:通過對鱗片微結(jié)構(gòu)的觀察分析,獲得了鱗片單元體的形態(tài)、結(jié)構(gòu)特征參數(shù)及整體分布規(guī)律,提取了各區(qū)域微觀結(jié)構(gòu)的主要尺寸。選取鱗片后區(qū)具有規(guī)則分布的微觀結(jié)構(gòu)作為生物原型,建立了具有鱗片型仿生表面的三維簡化模型。通過對具有鱗片型微結(jié)構(gòu)仿生表面的FLUENT模擬,分析了仿生表面的困水、漩渦等流體力學(xué)特性,并揭示了減阻機(jī)理。即:在微結(jié)構(gòu)前表面附近形成了低速的渦漩,穩(wěn)定了邊界層內(nèi)流體的運(yùn)動(dòng),進(jìn)而形成了低速穩(wěn)定態(tài)的"困水"區(qū)域,起到了流體潤滑的作用,形成了明顯的減阻效果。仿生樣件阻力拖拽試驗(yàn)結(jié)果表明:這種微結(jié)構(gòu)在低速時(shí)具有較好的減阻效果,且隨著來流速度的增加,減阻率呈現(xiàn)出降低的趨勢。在v=0.66 m·s-1時(shí),減阻效果最好,最大減阻率為2.805%。通過對仿生樣件的FLUENT模擬及阻力拖拽試驗(yàn)研究,優(yōu)化出鱗片微結(jié)構(gòu)的最優(yōu)參數(shù)組合,即鱗嵴高度為0.05mm,鱗嵴寬度為0.45 mm,相鄰鱗嵴之間的距離為0.20 mm,來流速度為0.70 m·s-1。鱗嵴高度對仿生表面的減阻效果具有顯著性的影響,而其它因素影響并不顯著。通過正交試驗(yàn)獲得了影響船板底面滑行阻力因素的主次順序?yàn)榇鍢邮酱鍢蛹呐渲厍斑M(jìn)速度,得到的最優(yōu)參數(shù)組合為前進(jìn)速度v=0.4 m.s-1、配重為0.7 kg、仿生船板樣件,此時(shí)減阻效果最佳,最大減阻率為22.90%。通過對仿生船板樣件在泥漿介質(zhì)中的Fluent模擬,獲得了船板樣件表面附近的泥漿壓力及速度的分布情況,得到仿生船板樣件的最佳減阻率為28.50%。本研究通過對插秧機(jī)船板表面微觀結(jié)構(gòu)的仿生減阻研究,改善了船板底面的摩檫學(xué)特性,實(shí)現(xiàn)減阻。該研究是結(jié)構(gòu)仿生學(xué)在水田機(jī)械領(lǐng)域的拓展研究,也為在工程機(jī)械、農(nóng)業(yè)機(jī)械、交通運(yùn)輸?shù)阮I(lǐng)域的仿生減阻研究提供了參考。
[Abstract]:The ship board is one of the important parts of rice transplanter. In the process of working in paddy field and mud water environment, the contact between ship board and mud water forms a great sliding resistance, which causes serious energy waste and reduces the working efficiency at the same time. Therefore, it is of great significance to reduce the fluid resistance of transplanter. In this paper, with the aid of the project of National Natural Science Foundation: the study on drag reduction mechanism of scale-like biomimetic microstructures on the bottom surface of transplanters, a biomimetic surface with scale-like microstructures was designed with the surface microstructure of grass carp scales as a biological prototype. The characteristics of drag reduction are analyzed. The microstructural biomimetic method was applied to the ship board of rice transplanter, and the flow tribological characteristics and drag reduction performance of the mud on the bottom surface of the ship board were further studied. The main contents and conclusions are as follows: through the observation and analysis of the microstructures of the scales, the morphology, structural characteristic parameters and the overall distribution of the scales are obtained, and the main dimensions of the microstructures in each region are extracted. The microstructures with regular distribution in the posterior region of scales were selected as biological prototypes, and a simplified three-dimensional model with scale-like biomimetic surfaces was established. By FLUENT simulation of biomimetic surface with scale structure, the hydrodynamic characteristics of bionic surface, such as water trap and vortex, are analyzed, and the mechanism of drag reduction is revealed. That is, a low velocity vortex is formed near the front surface of the microstructure, which stabilizes the movement of the fluid in the boundary layer, and then forms the "trapped water" region in the low speed stable state, which plays the role of fluid lubrication and forms an obvious drag reduction effect. The drag and drag test results of bionic samples show that the drag reduction effect of the microstructures is better at low speed, and the drag reduction rate decreases with the increase of incoming flow velocity. The maximum drag reduction rate is 2.805 when VX is 0.66 m / s ~ (-1) and the maximum drag reduction rate is 2.805 m / s ~ (-1). Based on the FLUENT simulation and drag test of the biomimetic samples, the optimum parameters of the scale microstructures were optimized, namely, the height of the scales was 0.05 mm, the width of the scales was 0.45 mm, the distance between adjacent scales was 0.20 mm, and the flow velocity was 0.70 m ~ (-1). The scale ridge height had a significant effect on drag reduction of bionic surface, but other factors did not. Through the orthogonal test, the main and secondary order of the factors affecting the skidding resistance on the bottom surface of the ship's plate is obtained, which is the weight forward speed of the ship's plate model, the optimum parameter combination is the advance speed (v) 0.4 m.s-1, the counterweight is 0.7 kg, and the bionic ship plate sample. At this time, drag reduction effect is the best, the maximum drag reduction rate is 22.90. The distribution of mud pressure and velocity near the surface of the bionic ship plate sample is obtained by Fluent simulation in the mud medium. The optimum drag reduction rate of the bionic ship plate sample is 28.50. Based on the study of biomimetic drag reduction of the surface microstructure of the ship plate of the transplanter, the friction characteristics of the bottom surface of the ship plate are improved and the drag reduction is realized. This study is an extension of structural bionics in the field of paddy field machinery, and also provides a reference for bionic drag reduction research in construction machinery, agricultural machinery, transportation and other fields.
【學(xué)位授予單位】：沈陽農(nóng)業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：S223.91

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